High-efficiency wideband radio frequency power amplifier based on open-loop resonant ring and design method thereof

Abstract

The application discloses a high-efficiency broadband radio frequency power amplifier based on an open resonant ring and a design method thereof, and at least comprises a broadband input matching network, a transistor circuit and an output matching network, wherein the output matching network is provided with at least an open resonant ring second harmonic matching network and a broadband fundamental wave matching network, and the open resonant ring second harmonic matching network is composed of a two-port rectangular double-loop open resonant ring. By using the low-resistance characteristic of the open resonant ring in the stop band, the application can match the second harmonic at the output end, and the second harmonic matching and the fundamental wave matching are carried out separately, so that the second harmonic and the fundamental wave can be well matched to the optimal output impedance at the same time, thereby improving the drain efficiency and the working bandwidth.

Description

Technical Field

[0001] This invention relates to the field of microwave radio frequency communication, specifically to a radio frequency power amplifier, and more particularly to a high-efficiency broadband radio frequency power amplifier based on an open-loop resonant ring and its design method. Background Technology

[0002] With the rapid development of wireless communication technology, radio frequency (RF) communication devices are required to have superior performance. Power amplifiers, as one of the main components of RF communication devices, are widely used in indoor short-range wireless communication, urban long-range wireless communication, radar communication, and satellite communication. The power amplifier is the most critical component in an RF communication transmitter, and its specifications directly affect the transmitter's performance. For example, the power amplifier accounts for 80% of the RF transmitter's energy consumption; its efficiency directly affects the transmitter's energy utilization rate. Furthermore, the bandwidth of the power amplifier determines the operating bandwidth of the RF transmitter, and bandwidth often determines the information transmission rate; the wider the bandwidth, the faster the information propagates.

[0003] On the one hand, to meet the requirements of large-area coverage in modern wireless communication networks, network operators have deployed a large number of communication base stations. However, a large number of communication base stations also means huge energy consumption. Therefore, in order to meet the concept of green and sustainable development, the high efficiency of the radio frequency power amplifier, the most core component of the communication base station transmitter, is crucial. On the other hand, in order to process signals in a wider frequency range, the operating bandwidth of the radio frequency transmitter should also be widened as much as possible. Therefore, a power amplifier with a wide bandwidth is also very necessary.

[0004] See Figure 1 The diagram shows the structure of a conventional power amplifier. Currently, research on improving power amplifier efficiency mostly involves adding harmonic control networks, such as F / F, at the output of the power amplifier chip. -1 While this type of amplifier can significantly improve the efficiency of power amplifiers, the introduced harmonic control network exhibits strong dispersion, causing the optimal output impedance of the power amplifier to vary greatly with frequency. Therefore, high efficiency can only be achieved within a relatively narrow frequency range. Current research on improving the bandwidth of power amplifiers mostly employs a matching network shared between the transistor's drain high-order harmonics and the fundamental frequency, such as connecting F / F... -1 Class J power amplifiers, although the output dispersion is not severe, share the same matching network for the fundamental and higher harmonics, resulting in limited design freedom and difficulty in achieving perfect matching between the harmonics and the fundamental. Therefore, their efficiency is not very high.

[0005] To address the current technical challenges, it is necessary to design a broadband high-efficiency power amplifier that enables its output matching network to achieve good matching between the fundamental and harmonic frequencies, while ensuring that the harmonic matching module does not introduce significant dispersion effects, thereby improving both efficiency and bandwidth. Summary of the Invention

[0006] To overcome the difficulties in the prior art, this invention proposes a high-efficiency broadband power amplifier based on an open-loop resonator and its design method. The open-loop resonator is used as the second harmonic matching module at the output end, and a series stepped impedance microstrip line structure is used as the output fundamental broadband matching module and the input broadband matching network.

[0007] To overcome the existing technical difficulties, the technical solution of the present invention is as follows:

[0008] A high-efficiency broadband RF power amplifier based on an open-circuit resonator includes at least a broadband input matching network, a transistor circuit, and an output matching network. The output matching network includes at least an open-circuit resonator second harmonic matching network and a broadband fundamental frequency matching network. The open-circuit resonator second harmonic matching network is composed of a two-port rectangular double-ring open-circuit resonator.

[0009] As a further improvement, the second harmonic matching network of the open resonant ring and the broadband fundamental frequency matching network are independent of each other and are used to complete the second harmonic matching and fundamental frequency matching respectively.

[0010] As a further improvement, in the two-port rectangular double-ring open-loop resonant ring, the outer ring is single-open and the inner ring is double-open; wherein, port 1 of the open-loop resonant ring is connected to the drain of the power amplifier transistor and the bias network, and port 2 of the open-loop resonant ring is connected to the broadband fundamental matching network, which is used to match the second harmonic output impedance to the high-efficiency region of the Smith chart.

[0011] As a further improvement, the second harmonic matching network of the open resonant ring is equivalent to six sets of parallel coupled microstrip lines PCTL1, PCTL2, PCTL3, PCTL4, PCTL5, and PCTL6. PCTL1 and PCTL4 are connected in series with port 1 and port 2, respectively, and a microstrip line TL1 of equal width is connected in series between PCTL1 and PCTL4. PCTL2 is connected in parallel with PCTL1 at port 1 and its other end is connected in series with PCTL3. PCTL5 is connected in parallel with PCTL4 at port 2 and its other end is connected in series with PCTL6. The other ends of PCTL3 and PCTL6 are open circuits.

[0012] Because of its symmetrical structure, the input impedance of the open-circuit resonator can be obtained using the odd-even mode analysis method, which specifically includes the following steps:

[0013] In a four-port parallel-coupled microstrip line, when two ports on the same side are open-circuited, what is the input impedance Z of the other port? ine for:

[0014]

[0015] When the two ports on the same side are short-circuited, the input impedance Z of the other port is... ino for:

[0016]

[0017] Z 0e and Z 0o These are the even-mode and odd-mode characteristic impedances of the parallel-coupled microstrip line, respectively, θ' MT It is half the electrical length of the parallel-coupled microstrip line.

[0018] When considering only the two ports of the parallel-coupled microstrip line on the same microstrip line, according to the odd-even mode analysis method, the impedance matrix [Z] of one port is:

[0019]

[0020] When a two-port parallel-coupled microstrip line has one port (port 2) connected to a load Z, L At that time, the S-parameters of the parallel-coupled microstrip line are:

[0021]

[0022] Based on the S-parameters, the input impedance Z of the other port (port 1) of the two-port parallel coupled line is obtained. in1 for:

[0023]

[0024] After symmetrically separating the open-circuit resonator along the input and output port midlines using the odd-even mode analysis method, it can be divided into two structurally identical parts. Each part can be considered as two sets of parallel coupled microstrip lines PCTL1 and PCTL0 connected in parallel, where PCTL1 is connected to a characteristic impedance of Z. 10 The microstrip line TL0 has an electrical length of θ'. g (Half the electrical length of TL1), PCTL0 is the equivalent circuit unit after PCTL2 is combined with PCTL3.

[0025] In even mode, with TL0 open-circuited, its input impedance Z e0 for:

[0026] Z e0 =-jZ 01 cotθ′ g (6)

[0027] Substituting into formula (5), we obtain the input impedance Z of PCTL1. e1 for:

[0028]

[0029] Where θ' r1 It is half the electrical length of PCTL1.

[0030] PCTL0 input impedance Z oc for:

[0031]

[0032] Where θ' r2 The electrical length of PCTL0 indicates the input impedance Z of the open-circuit resonant cyclotron mode. even for:

[0033]

[0034] In the odd-mode case, with the short end of TL0 open, its input impedance Z o0 for:

[0035] Z o0 =jZ 01 tanθ′ g (10)

[0036] Substituting into formula (5), we obtain the input impedance Z of PCTL1. o1 for:

[0037]

[0038] The odd-mode input impedance Z of the open-circuit resonant ring odd for:

[0039]

[0040] Similarly, replace Z in formula (5) with formula (9) and formula (12). ine With Z ino The input impedance Z of the open-circuit resonator under load can be obtained. inr

[0041]

[0042] Calculations using Matlab software demonstrate that the dispersion effect of the second harmonic matching network with an open resonant ring structure is not severe, and therefore it can be used in the design of broadband power amplifiers.

[0043] As a further improvement, the broadband fundamental wave matching network is composed of cascaded microstrip lines.

[0044] As a further improvement, the broadband input matching network is composed of cascaded microstrip lines.

[0045] As a further improvement, the broadband fundamental matching network employs a series stepped impedance microstrip line to match the 50Ω load impedance to the optimal output impedance at the output of the open-circuit resonator in the 1.2GHz–3.1GHz frequency range, thereby improving the power amplifier efficiency.

[0046] As a further improvement, the broadband input matching network employs a series stepped impedance microstrip line to match the 50Ω impedance of the signal source to the optimal input impedance of the power amplifier chip within the 1.2GHz–3.1GHz frequency range.

[0047] This invention also discloses a design method for a high-efficiency broadband RF power amplifier based on an open-circuit resonator, comprising at least the following steps:

[0048] Step S1: Determine the operating frequency and transistor type of the power amplifier;

[0049] Step S2: Perform load pulling on the power amplifier transistors used, including fundamental impedance pulling and second harmonic impedance pulling, to determine the optimal power and efficiency impedance regions of the transistor drain fundamental and second harmonic in the Smith chart.

[0050] Step S3: Design the second harmonic matching network of the open-loop resonator. The specific process is as follows:

[0051] Based on the optimal impedance region for the second harmonic obtained in step S2, the input impedance Z of the open-circuit resonator is determined. inr The odd-mode characteristic impedance Z of the open-circuit resonator is determined according to the following formula. 0o The characteristic impedance Z of the sum and even modes 0e PCTL1 electrical length θ r1 PCTL2 electrical length θ r2 and TL1 electrical length θ g During this process, the load impedance Z of the open-loop resonant ring... L The default value is 50Ω. Since the real part of the input impedance of the open-circuit resonator is almost zero during second harmonic matching, Z... L The value of has little effect on the real part of the input impedance of the split-ring resonator. The design formula is as follows:

[0052]

[0053] Here Z even With Z odd Z represents the even-mode input impedance and odd-mode input impedance of the second harmonic matching network of the open-loop resonant ring, respectively. e1 With Z o1Z represents the input impedance of PCTL1 in the even-mode and odd-mode cases of an open-circuit resonant ring, respectively. oc θ' is the input impedance of PCTL0. r2 =θ r1 +θ r2 ,θ' r1 =θ r1 / 2,θ' g =θ g / 2.

[0054] Step S4: Design the output fundamental frequency matching module. The specific process is as follows:

[0055] First, convert the optimal impedance of the fundamental frequency at the transistor drain to the output impedance of the secondary matching network of the split-ring resonator using the following formula; at this time, Z in the formula L Z should be the optimal impedance of the fundamental frequency at the transistor drain. inr The optimal impedance for the fundamental frequency at the output of the secondary matching network of the split-ring resonator is determined, while the parameters of other split-ring resonators are already fixed. A wide-range fundamental frequency matching module is then designed to match the 50Ω load to the optimal impedance at the output of the secondary matching network.

[0056]

[0057] Step S5: Source-pull transistors and design a wideband input matching module;

[0058] Step S6: Tune and optimize the overall circuit of the power amplifier.

[0059] As a preferred technical solution, the circuit model of the open resonant ring second harmonic matching network can be equivalent to six sets of parallel coupled microstrip lines PCTL1, PCTL2, PCTL3, PCTL4, PCTL5, and PCTL6. PCTL1 and PCTL4 are connected in series with port 1 and port 2, respectively, and a microstrip line TL1 of equal width is connected in series between PCTL1 and PCTL4. PCTL2 is connected in parallel with PCTL1 at port 1 and its other end is connected in series with PCTL3. PCTL5 is connected in parallel with PCTL4 at port 2 and its other end is connected in series with PCTL6. The other ends of PCTL3 and PCTL6 are open circuits.

[0060] Compared with the prior art, the present invention has the following technical effects:

[0061] 1. The split-ring second harmonic matching network of the present invention has a low input resistance value in the stopband frequency range, which perfectly matches the low resistance characteristic of the second harmonic frequency range of high-efficiency power amplifiers, thereby improving drain efficiency. Furthermore, compared with traditional parallel microstrip line second harmonic matching modules, the split-ring second harmonic matching network of the present invention can provide low input resistance over a wider frequency range, achieving high efficiency over a broader range.

[0062] 2. Compared to traditional parallel microstrip line second harmonic matching modules, the open-loop second harmonic matching network of this invention does not introduce significant dispersion effects, thus stabilizing the optimal output impedance change at the output point of the second harmonic matching module. This allows the fundamental matching module to complete impedance matching over a wider frequency range. Compared to traditional power amplifiers where output matching is performed by a single network simultaneously controlling the fundamental and harmonic frequencies, the power amplifier of this invention performs second harmonic and fundamental frequency matching separately, working in tandem for higher efficiency.

[0063] 3. The open-loop second harmonic matching network of the present invention can be applied to the radio frequency power amplifier module in 5G communication base stations with slight modifications. Its high efficiency can save energy consumption of communication base stations and reduce the overall operating cost of communication base stations. Attached Figure Description

[0064] Figure 1 This is a block diagram of a traditional power amplifier;

[0065] Figure 2 This is a block diagram of the high-efficiency broadband power amplifier based on an open-loop resonant ring according to the present invention;

[0066] Figure 3 This is the layout and equivalent schematic diagram of the second harmonic matching network of the open resonant ring of the present invention;

[0067] Figure 4 This is the resonant unit of the second harmonic matching network of the open resonant ring of the present invention;

[0068] Figure 5 These are the even and odd modes of the equivalent schematic diagram of the second harmonic matching network of the open resonant ring of the present invention;

[0069] Figure 6 These are the S-parameters of the second harmonic matching network of the open resonant ring of the present invention;

[0070] Figure 7 The present invention relates to the high-efficiency broadband power amplifier output matching network based on an open resonant ring, which shows the variation of input impedance with frequency and the high-efficiency impedance region driven by the load.

[0071] Figure 8This is a schematic diagram of the large-signal simulation results of the high-efficiency broadband power amplifier based on the open-loop resonator of this invention. Detailed Implementation

[0072] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0073] See Figure 2 This paper presents a high-efficiency broadband RF power amplifier based on an open-circuit resonator, comprising an open-circuit resonator as a second harmonic matching network, a broadband fundamental frequency matching network, and a broadband input matching network. The open-circuit resonator's second harmonic matching network and fundamental frequency output matching network are independent of each other, allowing for separate second harmonic matching and fundamental frequency matching, thereby improving the power amplifier's efficiency. Combined with a broadband input matching network, high efficiency can be achieved over a wide frequency range.

[0074] See Figure 3 The second harmonic resonator module network proposed in this invention consists of a two-port rectangular double-ring open-loop resonator. The outer ring of the open-loop resonator has a single opening, while the inner ring has two openings. Port 1 of the open-loop resonator is connected to the drain and bias network of the power amplifier chip, and port 2 is connected to a broadband fundamental frequency matching network, which matches the second harmonic output impedance to the high-efficiency region of the Smith chart. The main components of the open-loop resonator circuit model can be equivalently represented by six sets of parallel coupled microstrip lines PCTL1, PCTL2, PCTL3, PCTL4, PCTL5, and PCTL6. PCTL1 and PCTL4 are connected in series with ports 1 and 2, respectively, and a microstrip line TL1 of equal width is connected in series between PCTL1 and PCTL4. PCTL2 is connected in parallel with PCTL1 at port 1, and its other end is connected in series with PCTL3. PCTL5 is connected in parallel with PCTL4 at port 2, and its other end is connected in series with PCTL6. The other ends of PCTL3 and PCTL6 are open-circuited. Because it is a symmetrical structure, the input impedance of the open-circuit resonator can be obtained by using the odd-even mode analysis method.

[0075] The resonant unit of the open-loop resonator of this invention is a parallel-coupled microstrip line. Firstly, regarding... Figure 4 The resonant unit in the diagram is analyzed for both even and odd modes. In the even-mode case, the symmetry plane of the input and output ports of the resonant unit is open-circuited; in the odd-mode case, the symmetry plane of the input and output ports is short-circuited. For the open-circuit case of two ports on the same side, the input impedance Z of the other port is... ine for:

[0076]

[0077] When the two ports on the same side are short-circuited, the input impedance Z of the other port is... odd for:

[0078]

[0079] Z 0e and Z 0o These are the even-mode and odd-mode characteristic impedances of the parallel-coupled microstrip line, respectively, θ' MT It is half the electrical length of the parallel-coupled microstrip line.

[0080] According to the parity-modulus analysis method, the impedance matrix [Z] of one port is:

[0081]

[0082] The output port (port 2) of the resonant unit is connected to the load Z. L When, its S-parameters are:

[0083]

[0084] Based on the S-parameters, the input impedance Z at the input port (port 1) of the resonant unit is obtained. in1 for:

[0085]

[0086] Reference Figure 5 As shown, after symmetrically separating the open-circuit resonator along the midline of the input and output ports using the odd-even mode analysis method, it can be divided into two structurally identical parts. Each part can be considered as two sets of parallel coupled microstrip lines PCTL1 and PCTL0 connected in parallel, where PCTL1 is connected to a characteristic impedance of Z. 01 The microstrip line TL0 has an electrical length of θ'. g (Half of the TL1 electrical length), PCTL0 is Figure 3 The equivalent circuit unit after combining PCTL2 and PCTL3.

[0087] In even mode, with TL0 open-circuited, its input impedance Z e0 for:

[0088] Z e0 =-jZ 01 cotθ′ g (6)

[0089] Substituting into formula (5), the input impedance Z of PCTL1 e1 for:

[0090]

[0091] Where θ' r1 It is half the electrical length of PCTL1.

[0092] PCTL0 is open-circuited, its input impedance Zoc for:

[0093]

[0094] Where θ' r2 Given the electrical length of PCTL0, the input impedance Z of the open-circuit resonant cyclotron mode is... even for:

[0095]

[0096] In the odd-mode case, with the short end of TL0 open, its input impedance Z o0 for:

[0097] Z o0 =jZ 01 tanθ′ g (10)

[0098] Substituting into formula (5), the input impedance Z of PCTL1 o1 for:

[0099]

[0100] The odd-mode input impedance Z of the open-circuit resonant ring odd for:

[0101]

[0102] Similarly, replace Z in formula (5) with formula (9) and formula (12). ine With Z ino The input impedance Z of the open-circuit resonator under load can be obtained. inr :

[0103]

[0104] Calculations using Matlab software demonstrate that the dispersion effect of the second harmonic matching network with an open resonant ring structure is not severe, and therefore it can be used in the design of broadband power amplifiers.

[0105] This invention also discloses a design method for a high-efficiency broadband power amplifier based on an open-loop resonator, specifically including the following steps:

[0106] Step S1: Determine the operating frequency, transistor type, and other specifications of the power amplifier;

[0107] Step S2: Perform load pulling on the power amplifier transistors used, including fundamental impedance pulling and second harmonic impedance pulling, to determine the optimal power and efficiency impedance regions of the transistor drain fundamental and second harmonic in the Smith chart.

[0108] Step S3: Design the second harmonic matching network of the open-loop resonator. The specific process is as follows:

[0109] Based on the optimal impedance region for the second harmonic obtained in step S2, the input impedance Z of the open-circuit resonator is determined. inr The odd-mode characteristic impedance Z of the open-circuit resonator is determined according to the following formula. 0o The characteristic impedance Z of the sum and even modes 0e PCTL1 electrical length θ r1 PCTL2 electrical length θ r2 and TL1 electrical length θ g During this process, the load impedance Z of the open-loop resonant ring... L The default value is 50Ω. Since the real part of the input impedance of the open-circuit resonator is almost zero during second harmonic matching, Z... L The value of does not have a significant impact on the real part of the input impedance of the open-circuit resonator.

[0110]

[0111] Here Z even With Z odd Z represents the even-mode input impedance and odd-mode input impedance of the second harmonic matching network of the open-loop resonant ring, respectively. e1 With Z o1 Z represents the input impedance of PCTL1 in the even-mode and odd-mode cases of an open-circuit resonant ring, respectively. oc θ' is the input impedance of PCTL0. r2 =θ r1 +θ r2 ,θ' r1 =θ r1 / 2,θ' g =θ g / 2.

[0112] Step S4: Design the output fundamental frequency matching module. The specific process is as follows:

[0113] First, convert the optimal impedance of the fundamental frequency at the transistor drain to the output impedance of the secondary matching network of the split-ring resonator using the following formula; at this time, Z in the formula L Z should be the optimal impedance of the fundamental frequency at the transistor drain. inr The optimal impedance of the fundamental frequency at the output of the secondary matching network of the split-ring resonator is determined, while the parameters of the other split-ring resonators are already fixed. Then, a wide fundamental frequency matching module is designed to match the 50Ω load to the optimal impedance at the output of the secondary matching network.

[0114]

[0115] Step S5: Source-pull transistors and design a wideband input matching module;

[0116] Step S6: Tune and optimize the overall power amplifier circuit. (Refer to...) Figure 6 As shown, the open-circuit resonator of the present invention has a band-stop effect, which perfectly matches the characteristic of low resistance of the optimal second harmonic output impedance of the power amplifier, and at the same time has good conduction characteristics in the fundamental frequency range.

[0117] Reference Figure 7 As shown, it can be seen that the fundamental and second harmonic impedances at the drain of the power amplifier transistor largely overlap with the high-efficiency impedance region obtained by load pull, indicating that the open resonant ring second harmonic matching network and the series step impedance fundamental matching network in the present invention can achieve good impedance matching over a wide frequency range.

[0118] Reference Figure 8 The diagram shows the large-signal simulation results of the high-efficiency broadband power amplifier based on the split-ring resonator of this invention. On one hand, the separate matching of the second harmonic and the fundamental frequency results in high drain efficiency for the power amplifier. On the other hand, the second harmonic matching network based on the split-ring resonator of this invention does not exhibit significant dispersion effects, thus enabling a wide operating frequency range. Within the 1.2GHz–3.1GHz frequency range, the saturated drain efficiency of the power amplifier is above 60%, with an average saturated drain efficiency of approximately 70%, and reaches over 80% at 2.4GHz, truly achieving both broadband and high efficiency. Furthermore, within the operating frequency band, the saturated gain is in the range of 9dB–12dB, with most frequencies above 10dB, and the saturated output power is between 39dBm and 42dBm, with most frequencies above 41dBm.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-efficiency broadband RF power amplifier based on an open-circuit resonator, characterized in that, It includes at least a broadband input matching network, a transistor circuit, and an output matching network. The output matching network is provided with at least an open-loop second harmonic matching network and a broadband fundamental frequency matching network. The open-loop second harmonic matching network is composed of a two-port rectangular double-loop open-loop resonant ring. In a two-port rectangular double-ring open resonant ring, the outer ring is single-open and the inner ring is double-open. Port 1 of the open resonant ring is connected to the drain and bias network of the power amplifier transistor, and port 2 of the open resonant ring is connected to the broadband fundamental matching network, which is used to match the second harmonic output impedance to the high-efficiency region of the Smith chart. The second harmonic matching network of the open resonant ring is equivalent to six sets of parallel coupled microstrip lines PCTL1, PCTL2, PCTL3, PCTL4, PCTL5, and PCTL6. PCTL1 and PCTL4 are connected in series with port 1 and port 2, respectively, and a microstrip line TL1 of equal width is connected in series between PCTL1 and PCTL4. PCTL2 is connected in parallel with PCTL1 at port 1 and its other end is connected in series with PCTL3. PCTL5 is connected in parallel with PCTL4 at port 2 and its other end is connected in series with PCTL6. The other ends of PCTL3 and PCTL6 are open circuits.

2. The high-efficiency broadband RF power amplifier based on an open-circuit resonator according to claim 1, characterized in that, The open-loop resonant ring second harmonic matching network and the broadband fundamental wave matching network are independent of each other and are used to complete the second harmonic matching and fundamental wave matching respectively.

3. The high-efficiency broadband RF power amplifier based on an open-circuit resonator according to claim 1, characterized in that, The input impedance of the open-circuit resonator is obtained using the odd-even mode analysis method, where: In a four-port parallel-coupled microstrip line, when the two ports on the same side are open-circuited, the input impedance Z of the other port... ine for: (1) When the two ports on the same side are short-circuited, the input impedance Z of the other port is... ino for: (2) Among them, Z 0e and Z 0o These are the even-mode and odd-mode characteristic impedances of the parallel-coupled microstrip line, respectively. It is half the electrical length of the parallel-coupled microstrip line; When considering only the two ports of the parallel-coupled microstrip line on the same microstrip line, according to the odd-even mode analysis method, the impedance matrix [Z] of one port is: (3) When the two-port parallel coupled microstrip line port 2 is connected to load Z L At that time, the S-parameters of the parallel-coupled microstrip line are: (4) Based on the S-parameters, the input impedance Z of the other port of the two-port parallel coupled line, i.e., port 1, is obtained. in1 for: (5) After symmetrically separating the open-circuit resonator along the input and output port midlines using the odd-even mode analysis method, it can be divided into two structurally identical parts. Each part can be considered as two sets of parallel coupled microstrip lines PCTL1 and PCTL0 connected in parallel, where PCTL1 is connected to a characteristic impedance of Z. 01 The microstrip line TL0 has an electrical length of TL0. PCTL0 is half the electrical length of TL1, and PCTL2 is the equivalent circuit unit after PCTL2 is combined with PCTL3. In even mode, with TL0 open-circuited, its input impedance Z e0 for: (6) Substituting into formula (5), the input impedance Z of PCTL1 e1 for: (7) in It is half the electrical length of PCTL1; PCTL0 is open-circuited, its input impedance Z oc for: (8) in, Given the electrical length of PCTL0, the input impedance Z of the open-circuit resonant cyclotron mode is... even for: (9) In the odd-mode case, the TL0 terminal is short-circuited, and its input impedance Z o0 for: (10) Substituting into formula (5), we obtain the input impedance Z of PCTL1. o1 for: (11) The odd-mode input impedance Z of the open-circuit resonant ring odd for: (12) Replace Z in formula (5) with formula (9) and formula (12). ine With Z ino The input impedance Z of the open-circuit resonator under load can be obtained. inr : （13）。 4. The high-efficiency broadband RF power amplifier based on an open-circuit resonator according to claim 1, characterized in that, The broadband fundamental wave matching network is composed of cascaded microstrip lines.

5. The high-efficiency broadband RF power amplifier based on an open-circuit resonator according to claim 1, characterized in that, The broadband input matching network is composed of cascaded microstrip lines.

6. The high-efficiency broadband RF power amplifier based on an open-circuit resonator according to claim 4, characterized in that, The broadband fundamental matching network employs a series stepped impedance microstrip line to match the 50Ω load impedance to the optimal output impedance at the output of the open-circuit resonator in the 1.2GHz–3.1GHz frequency range, thereby improving the efficiency of the power amplifier.

7. The high-efficiency broadband RF power amplifier based on an open-circuit resonator according to claim 5, characterized in that, The broadband input matching network employs a series stepped impedance microstrip line to match the 50Ω impedance of the signal source to the optimal input impedance of the power amplifier chip within the 1.2GHz–3.1GHz frequency range.

8. The design method of a high-efficiency broadband RF power amplifier based on an open-circuit resonator as described in claim 1, characterized in that, At least the following steps are included: Step S1: Determine the operating frequency and transistor type of the power amplifier; Step S2: Perform load pulling on the power amplifier transistors used, including fundamental impedance pulling and second harmonic impedance pulling, to determine the optimal power and efficiency impedance regions of the transistor drain fundamental and second harmonic in the Smith chart. Step S3: Design the second harmonic matching network of the open-loop resonator. The specific process is as follows: Based on the optimal impedance region for the second harmonic obtained in step S2, the input impedance Z of the open-circuit resonator is determined. inr The odd-mode characteristic impedance Z of the open-circuit resonator is determined according to the following formula. 0o The characteristic impedance Z of the sum and even modes 0e PCTL1 electrical length PCTL2 electrical length and TL1 electrical length ; During this process, the load impedance Z of the open-loop resonant ring L The default value is 50Ω. Since the real part of the input impedance of the open-circuit resonator is almost zero during second harmonic matching, Z... L The value of has little effect on the real part of the input impedance of the split-ring resonator. The design formula is as follows: ； Among them, Z even With Z odd Z represents the even-mode input impedance and odd-mode input impedance of the second harmonic matching network of the open-loop resonant ring, respectively. e1 With Z o1 Z represents the input impedance of PCTL1 in the even-mode and odd-mode cases of an open-circuit resonant ring, respectively. oc The input impedance of PCTL0 is... , , ; Step S4: Design the output fundamental frequency matching module. The specific process is as follows: First, convert the optimal impedance of the fundamental frequency at the transistor drain to the output impedance of the secondary matching network of the split-ring resonator using the following formula; at this time, Z in the formula L Z should be the optimal impedance of the fundamental frequency at the transistor drain. inr The optimal impedance for the fundamental frequency at the output of the secondary matching network of the split-ring resonator is determined, while the parameters of other split-ring resonators are already fixed. A wide-range fundamental frequency matching module is then designed to match the 50Ω load to the optimal impedance at the output of the secondary matching network. ； Step S5: Source-pull transistors and design a wideband input matching module; Step S6: Tune and optimize the overall circuit of the power amplifier.

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